Japanese Unexamined Patent Publication (Kokai) No. 8-323575 describes an automatic tool changer, as a first prior art, which is generally used for machine tools such as machining centers. The tool changer comprises a tool magazine, disposed at one side of a column of the machine tool, for accommodating a plurality of tool pots, each of which receives a tool and moving the tool pots along an orbit to a predetermined position, and a tool changing arm for gripping the tool received in the tool pot positioned at the predetermined position and removing the tool from the tool pot with one of the grippers thereof. The tool changing arm rotates to the outside of the orbit so as to hold a tool received in the spindle with the other gripper and to change the new and old tools with each other. There is another type of tool changer in which the tool changing arm does not rotate 90 degrees but a separately provided sub-arm rotates 90 degrees to move the tool pot to a changing position from the tool magazine. Thereafter, the tool changing arm changes the tool on the spindle. In either type of the tool changers, the tools or the tool pots to be changed is rotated 90 degrees to the outside of the orbit.
Japanese Examined Patent Publication (Kokai) No. 5-85298 describes an automatic tool changer as a second prior art. A circular ring tool magazine has a plurality of tool pots and is rotationally supported at one side of a column. A tool changing arm conducts various motions for changing the tool on the spindle. The tool changing motion is composed of respective motions for holding a tool accommodated in the tool magazine, removing the tool from the tool pot and rotating the tool changing arm 90 degrees. A mechanism for conducting such various motions of the tool changing arm is provided adjacent the tool magazine.
Japanese Unexamined Patent Publication (Kokai) No. 2001-71228 describes an automatic tool changer as a third prior art. A circular tool magazine receives radially disposed tools in a plane with the tips of the tool oriented the center of the circle. The tool magazine is disposed on the ceiling of a splashguard enclosing the machining area. The tool to be changed is lowered from the tool magazine to a changing position where a tool changing arm changes the tool with one on the spindle.
According to the first prior art, the tool or the tool pot is rotated 90 degrees to the outside of the orbit of the tool magazine. Therefore, an extra space for allowing the tool changing motion is necessary at the outside of the tool magazine. This is a problem for spacesaving.
According to the second prior art, the problem of the first prior art is solved. However, as described above, the tool changing arm must conduct various motions. Therefore, there are problems that the configuration of the tool changing arm becomes complex and its size is increased.
According to the third prior art, the problems of the first and second prior art are solved. However, because of the radial disposition of the tools in a plane, the number of the tools stored in the tool magazine is reduced compared with a tool magazine which has the same diameter and accommodates the tools disposed perpendicular to the disk.
The invention is directed to solving the above-describe problems of the prior art, and the object of the invention is to provide a simple and compact tool changer for a machine tool, the tool changer changing tools between an indexable tool magazine having a plurality of tool pots for receiving tools and a spindle.